"I do not want to say anything regarding politics. But could it be because of pressure from the UN or others? We do not know exactly but there might be something."

Myanmar's ruling generals have kept the Nobel peace laureate under house arrest for nearly 14 of the last 20 years, since her NLD party won a landslide victory in the 1988 elections.

Jared Genser, Aung San Suu Kyi's international legal counsel, said the latest postponement in the trial was another attempt by the military government to deflect foreign criticism.

"It is in some ways a smart move – push off the verdict until the middle of August when numerous government and UN officials around the world will be on vacation," he said in a statement.

"But it remains to be seen whether this ploy will work or if anticipation will be heightened in the run-up to the issuance of the verdict."

Earlier on Friday riot police surrounded the prison and police trucks patrolled the city following warnings in the military-controlled state media that protests against a guilty verdict would not be tolerated.

'Sham trial'

Critics have said the trial is a sham based on charges trumped up by the military in order to keep her behind bars through elections planned for next year.

But neither international outrage nor offers of closer ties with the US if she is freed appear to have been able to deflect the military rulers' apparent determination to neutralise, if not jail, her.

Security was heavy around the Insein prison where the trial was being held [AFP]

Benjamin Zawacki, a Myanmar specialist for human rights watchdog Amnesty International, said the repeated adjournments were orchestrated by the military rulers to make the court appear fair and impartial.

"It's very suspicious since most courts wouldn't take this long," he said. "We knew the verdict was decided long ago. This is clearly political and not legal."

A diplomatic source who attended the proceedings said the verdict was delayed "because of the need to interpret legal terms relating to the 1974 constitution".

Aung San Suu Kyi's legal team has argued that she should be acquitted because the law she is charged under was part of the 1974 constitution, which is no longer in use.

But the prosecution argued that the charges are relevant because the 1974 constitution was still in force when Aung San Suu Kyi's latest period of house arrest commenced in 2003.

Verdicts had also been expected in the cases of John Yettaw, the US citizen, and of Khin Win and Win Ma Ma, the two female aides who were living with Aung San Suu Kyi at the lakeside property.

An unnamed Western diplomat in Yangon said the military government could be stalling as a result of international condemnation of the trial.

"The regime wants to take its time because of the mounting pressure it is under," the diplomat said. "They're being attacked from all fronts and they have a lot of things to consider."